Carpal Tunnel Syndrome

Overview

Practice Essentials

Carpal tunnel syndrome (CTS) is a collection of characteristic symptoms and signs that occurs following compression of the median nerve within the carpal tunnel. Usual symptoms include numbness, paresthesias, and pain in the median nerve distribution. These symptoms may or may not be accompanied by objective changes in sensation and strength of median-innervated structures in the hand.[1, 2] See image below.

The hands of an 80-year-old woman with a several-year history of numbness and weakness are shown in this photo. Note severe thenar muscle (abductor pollicis brevis, opponens pollicis) wasting of the right hand, with preservation of hypothenar eminence.

Workup

Electrophysiologic studies,[3, 4, 5] including electromyography (EMG) and nerve conductions studies (NCS), are the first-line investigations in suggested carpal tunnel syndrome (CTS).[6] Abnormalities on electrophysiologic testing, in association with specific symptoms and signs, are considered the criterion standard for CTS diagnosis. In addition, other neurologic diagnoses can be excluded with these test results.

Electrophysiologic testing also can provide an accurate assessment of how severe the damage to the nerve is, thereby directing management and providing objective criteria for the determination of prognosis.

Many clinical neurophysiology laboratories are now using ultrasonography as an adjunct to electrodiagnostic studies. Ultrasonography potentially can identify space-occupying lesions in and around the median nerve, confirm abnormalities in the median nerve (eg, increased cross-sectional area) that can be diagnostic of CTS, and help to guide steroid injections into the carpal tunnel.[7, 8, 9]

Magnetic resonance imaging (MRI) of the carpal tunnel is particularly useful preoperatively if a space-occupying lesion in the carpal tunnel is suggested.

Management

Given that CTS is associated with low aerobic fitness and increased body mass index (BMI), it makes some inherent sense to provide the patient with an aerobic fitness and weight-loss program. Stationary biking, cycling, or any other exercise that puts strain on the wrists probably should be avoided. The use of modalities (in particular therapeutic ultrasound) may provide short-term relief in some patients.[10, 11, 12]

Most individuals with mild to moderate CTS (according to electrophysiologic data) respond to conservative management, usually consisting of splinting the wrist at nighttime for a minimum of 3 weeks.[10, 13, 14]

Steroid injection into the carpal tunnel has been shown to be of long-term benefit and can be tried if more conservative treatments have failed.[15]

Patients whose condition does not improve following conservative treatment and patients who initially are in the severe CTS category should be considered for surgery.[16] Surgical release of the transverse ligament provides high initial success rates (greater than 90%), with low rates of complication; however, it has been suggested that the long-term success rate may be much lower than previously thought (approximately 60% at 5 y). Success rates also are considerably lower for individuals with normal electrophysiologic studies.[17, 18, 19]

Pathophysiology

Until the advent of electrophysiologic testing in the 1940s, carpal tunnel syndrome (CTS) commonly was thought to be the result of compression of the brachial plexus by cervical ribs and other structures in the anterior neck region. It is now known that the median nerve is damaged within the rigid confines of the carpal tunnel, initially undergoing demyelination followed by axonal degeneration. Sensory fibers often are affected first, followed by motor fibers. Autonomic nerve fibers carried in the median nerve also may be affected.

The cause of the damage is subject to some debate; however, it seems likely that abnormally high carpal tunnel pressures exist in patients with CTS. This pressure causes obstruction to venous outflow, back pressure, edema formation, and ultimately, ischemia in the nerve.

The risk of development of CTS appears to be associated, at least in part, with a number of different epidemiologic factors, including genetic, medical, social, vocational, avocational, and demographic.[20] A complex interaction probably exists between some or all these factors, eventually leading to the development of CTS. Definite causative factors, however, are far from clear.

Epidemiology

Frequency

United States

The incidence of carpal tunnel syndrome is 1-3 cases per 1000 subjects per year; prevalence is approximately 50 cases per 1000 subjects in the general population. Incidence may rise as high as 150 cases per 1000 subjects per year, with prevalence rates greater than 500 cases per 1000 subjects in certain high-risk groups.

International

A paucity of population-based studies of carpal tunnel syndrome (CTS) exists; however, the incidence and prevalence in developed countries seems similar to the United States (eg, incidence in the Netherlands is approximately 2.5 cases per 1000 subjects per year; prevalence in the United Kingdom is 70-160 cases per 1000 subjects).[21, 22, 23] CTS is almost unheard of in some developing countries (eg, among nonwhite South Africans).

Mortality/Morbidity

Carpal tunnel syndrome is not fatal, but it can lead to complete, irreversible median nerve damage, with consequent severe loss of hand function, if left untreated.

Race

Whites are probably at highest risk of developing carpal tunnel syndrome (CTS). The syndrome appears to be very rare in some racial groups (eg, nonwhite South Africans).[23] In North America, white US Navy personnel have CTS at a rate 2-3 times that of black personnel.[24]

Sex

The female-to-male ratio for carpal tunnel syndrome is 3-10:1.

Age

The peak age range for development of carpal tunnel syndrome (CTS) is 45-60 years. Only 10% of patients with CTS are younger than 31 years.

Presentation

History

The patient's history often is more important than the physical examination in making the diagnosis of carpal tunnel syndrome (CTS).

Numbness and tingling

Among the most common complaints, patients will reveal that their hands fall asleep or that things slip from their fingers without their noticing (loss of grip, dropping things); numbness and tingling also are commonly described.

Symptoms are usually intermittent and are associated with certain activities (eg, driving, reading the newspaper, crocheting, painting). Nighttime symptoms that wake the individual are more specific to CTS, especially if the patient relieves symptoms by shaking the hand/wrist. Bilateral CTS is common, although the dominant hand is usually affected first and more severely than the other hand.

Complaints should be localized to the palmar aspect of the first to the fourth fingers and the distal palm (ie, the sensory distribution of the median nerve at the wrist). Numbness existing predominantly in the fifth finger or extending to the thenar eminence or dorsum of the hand should suggest other diagnoses. A surprising number of CTS patients are unable to localize their symptoms further (eg, whole hand/arm feeling dead). This generalized numbness may indicate autonomic fiber involvement and does not exclude CTS from the diagnosis.

Pain

The sensory symptoms above commonly are accompanied by an aching sensation over the ventral aspect of the wrist. This pain can radiate distally to the palm and fingers or, more commonly, extend proximally along the ventral forearm.

Pain in the epicondylar region of the elbow, upper arm, shoulder, or neck is more likely to be due to other musculoskeletal diagnoses (eg, epicondylitis) with which CTS commonly is associated. This more proximal pain also should prompt a careful search for other neurologic diagnoses (eg, cervical radiculopathy).

Autonomic symptoms

Not infrequently, patients report symptoms in the whole hand. Many patients with CTS also complain of a tight or swollen feeling in the hands and/or temperature changes (eg, hands being cold/hot all the time).

Many patients also report sensitivity to changes in temperature (particularly cold) and a difference in skin color. In rare cases, there are complaints of changes in sweating. In all likelihood, these symptoms are due to autonomic nerve fiber involvement (the median nerve carries most of the autonomic fibers to the hand).

Weakness/clumsiness - Loss of power in the hand (particularly for precision grips involving the thumb) does occur; in practice, however, loss of sensory feedback and pain is often a more important cause of weakness and clumsiness than is loss of motor power per se.

Physical

Clinical examination is important to rule out other neurologic and musculoskeletal diagnoses; however, the examination often contributes little to the confirmation of the diagnosis of carpal tunnel syndrome (CTS).

Sensory examination

Abnormalities in sensory modalities may be present on the palmar aspect of the first 3 digits and radial one half of the fourth digit. Semmes-Weinstein monofilament testing or 2-point discrimination may be more sensitive in picking this up; however, in the author's experience, pinprick sensation is as good as any test.

Motor examination - Wasting and weakness of the median-innervated hand muscles (LOAF muscles) may be detectable.

L - First and second lumbricals

O - Opponens pollicis

A - Abductor pollicis brevis

F - Flexor pollicis brevis

Special tests - No good clinical test exists to support the diagnosis of CTS.

Hoffmann-Tinel sign

Gentle tapping over the median nerve in the carpal tunnel region elicits tingling in the nerve's distribution.

This sign still is commonly looked for, despite the low sensitivity and specificity.

Phalen sign

Tingling in the median nerve distribution is induced by full flexion (or full extension for reverse Phalen) of the wrists for up to 60 seconds

This test has 80% specificity but lower sensitivity.

The carpal compression test[25]

This test involves applying firm pressure directly over the carpal tunnel, usually with the thumbs, for up to 30 seconds to reproduce symptoms.

Reports indicate that this test has a sensitivity of up to 89% and a specificity of 96%.

Palpatory diagnosis

This test involves examining the soft tissues directly overlying the median nerve at the wrist for mechanical restriction.

This palpatory test has been noted to have a sensitivity of over 90% and a specificity of 75% or greater.

The square wrist sign

The ratio of the wrist thickness to the wrist width is greater than 0.7.

This test has a modest sensitivity/specificity of 70%.

Several other tests have been advocated, but they rarely provide additional information beyond that which the Phalen and square wrist signs provide.

Causes

Note that carpal tunnel syndrome (CTS) is associated with many different factors.[26] In particular, the more the hand and wrist are used, the greater the symptoms. This observation does not necessarily mean that using the hand and wrist causes the syndrome or that more median nerve damage ensues. Association should not be assumed to signify causation.

Workup

Laboratory Studies

No blood tests exist for the diagnosis of carpal tunnel syndrome; however, laboratory testing for associated conditions (eg, diabetes) may be performed when clinically indicated.

Imaging Studies

No imaging studies are considered routine in the diagnosis of carpal tunnel syndrome (CTS).

Magnetic resonance imaging (MRI) of the carpal tunnel is particularly useful preoperatively if a space-occupying lesion in the carpal tunnel is suggested. Signal abnormality can be detected in the median nerve in some cases of CTS, but how these abnormalities correlate to diagnosis and physiologic severity is not clear. MRI does not rule out the multitude of other differential diagnoses and is time consuming and resource intensive.[30]

Many clinical neurophysiology laboratories are now using ultrasonography as an adjunct to electrodiagnostic studies. Ultrasonography potentially can identify space-occupying lesions in and around the median nerve, confirm abnormalities in the median nerve (eg, increased cross-sectional area) that can be diagnostic of CTS, and help to guide steroid injections into the carpal tunnel.[7, 8, 9]

Other Tests

Electrophysiologic studies,[3, 4, 5] including electromyography (EMG) and nerve conductions studies (NCS), are the first-line investigations in suggested carpal tunnel syndrome (CTS).[6] Abnormalities on electrophysiologic testing, in association with specific symptoms and signs, are considered the criterion standard for CTS diagnosis. In addition, other neurologic diagnoses can be excluded with these test results. NCS in a patient with CTS are seen in the images below.

Sensory nerve conduction studies from the left hand of a patient with a several-year history of numbness and weakness (responses from the median nerve in the right hand were completely absent). Note marked slowing of the conduction velocity (CV) to 29.8 and 25.5 m/s for digits 3 and 1, respectively (normal >50 m/s). The amplitude for both also is reduced markedly (normal >10). These findings are consistent with carpal tunnel syndrome.

Motor nerve conduction studies from the left hand of a patient with a several-year history of numbness and weakness (responses from the median nerve in the right hand were completely absent). Note that the conduction velocity (CV) across the carpal tunnel segment slows severely to 18.3 m/s (normal >50 m/s) and that the distal motor latency is prolonged at 6.3 ms (normal &lt; 4.2 ms). Amplitudes are low for the wrist and elbow stimulus sites at 4.7 mV (normal >5 mV), but amplitudes are 31% higher distal to the carpal tunnel (at the palm). This discrepancy may represent conduction block (neurapraxia) at the level of the carpal tunnel or coactivation of the ulnar branch to adductor pollicis. Needle electromyography is required to determine whether axonal loss is present.

Electrophysiologic testing also can provide an accurate assessment of how severe the damage to the nerve is, thereby directing management and providing objective criteria for the determination of prognosis. CTS is usually divided into mild, moderate, and severe; however, criteria for this assessment usually vary from lab to lab. In general, patients with mild CTS have sensory abnormalities alone on electrophysiologic testing, and patients with sensory plus motor abnormalities have moderate CTS. However, any evidence of axonal loss (eg, decreased or absent sensory or motor responses distal to the carpal tunnel or neuropathic abnormalities on needle EMG) is classified as severe CTS.

Changes in electrophysiologic results over time can be used to assess the success of various treatment modalities.

The American Association of Electrodiagnostic Medicine has published standards and guidelines that govern the minimum number of studies that should be performed to diagnose CTS.[4]

Other quantitative tests, such as thermography and vibrometry, have been shown to be inferior to electrophysiologic examination and, because they have not been supported by controlled studies, are not recommended.

Treatment

Rehabilitation Program

Physical Therapy

Given that carpal tunnel syndrome (CTS) is associated with low aerobic fitness and increased BMI, it makes some inherent sense to provide the patient with an aerobic fitness and weight-loss program. Stationary biking, cycling, or any other exercise that puts strain on the wrists probably should be avoided.

The use of modalities (in particular therapeutic ultrasound) may provide short-term relief in some patients.[10, 11, 12] A study by Incebiyik et al indicated that in patients with mild to moderate CTS, treatment with short-wave diathermy (SWD) can produce significant short-term benefits, including alleviation of clinical symptoms and pain and improvement of hand function. In the prospective, randomized, controlled, double-blind trial, 31 patients (58 wrists) with mild to moderate CTS were treated with a combination of a hot pack, nerve and tendon gliding exercises, and either SWD or placebo SWD, undergoing this therapy five times per week for three weeks. A variety of evaluation measures, including the Tinel sign test, Phalen sign test, carpel tunnel compression test, and Boston Carpal Tunnel Questionnaire (BCTQ) Symptom Severity and Functional Status scales, were used to assess patient outcomes. Significant improvements were found in the patients who underwent SWD but not in those who receivedthe placebo treatment.[31]

Additionally, yoga and carpal bone mobilization techniques have some weak evidence for reducing symptoms in the short term.[12, 32]

Occupational Therapy

Wrist splints with the wrist joint in neutral or slight extension (to be worn at nighttime for a minimum of 3-4 wk) have some evidence for efficacy. Certainly, they are low cost and have very low risk of adverse effects and therefore can be considered as an initial therapy.[14] No evidence suggests that a specific stretching/strengthening program for the hand and wrist is useful for treating carpal tunnel syndrome.[32] Massage and/or nerve-glide techniques offer no proven benefit.[12, 32] Work-site ergonomic assessment, equipment, and/or ergonomic positioning seem to not provide any benefit.[11, 33]

Medical Treatment

Most individuals with mild to moderate carpal tunnel syndrome (CTS; according to electrophysiologic data) respond to conservative management, usually consisting of splinting the wrist at nighttime for a minimum of 3 weeks. Many off-the-shelf wrist splints seem to work well, although theoretically, a custom-made splint in neutral is probably the best choice.[10, 13, 14]

Steroid injection into the carpal tunnel has been shown to be of long-term benefit and can be tried if more conservative treatments have failed.[15] Injections may also be worthwhile prior to surgical management or in cases in which surgery is relatively contraindicated (eg, because of pregnancy).[15, 34] Ultrasonographic measurements of the median nerve can help predict response to steroid injection.[35]

A double-blind, randomized, controlled study by Chen et al indicated that both direct and ultrasonographically guided corticosteroid injections in patients with idiopathic CTS lead to improvements in clinical signs and symptoms, physical function, and the majority of electrodiagnostic parameters. However, ultrasonographically guided injection in the study was associated with greater improvements in the Semmes-Weinstein monofilament test and digit 4 comparison study, as well as sensory nerve conduction velocity.[36]

A randomized clinical trial by Raeissadat et al indicated that in patients with mild to moderate CTS, a local progesterone injection produces improvement comparable to that from a corticosteroid injection, with functional outcome actually being superior to that from corticosteroid treatment. The study, which included 78 CTS patients, found no significant difference between the progesterone and corticosteroid groups with regard to factors such as pain and electrophysiologic findings, at 6-month follow-up, while functional status, as evaluated using the Boston/Levine symptom severity and functional status scale, was significantly better in the progesterone group.[37]

The anticonvulsants gabapentin and pregabalin, which have come to be administered for various types of neuropathic pain, can be used, off-label, for CTS.[38, 39]

Nonsteroidal anti-inflammatory drugs (NSAIDs) and/or diuretics may be of benefit against CTS in certain populations (eg patients with fluid retention or with wrist flexor tendinitis). The efficacy of gabapentin, diuretics, and NSAIDs is controversial, however, with guidelines from the American Academy of Orthopaedic Surgeons stating that oral agents are no better than placebo in the treatment of CTS.[40] Additionally, vitamin B-6 and B-12 supplements are of no proven benefit against the disorder.[12]

Surgical Intervention

Patients whose condition does not improve following conservative treatment and patients who initially are in the severe carpal tunnel syndrome (CTS) category (as defined by electrophysiologic testing) should be considered for surgery.[16] Surgical release of the transverse ligament provides high initial success rates (greater than 90%), with low rates of complication; however, it has been suggested that the long-term success rate may be much lower than previously thought (approximately 60% at 5 y). Success rates also are considerably lower for individuals with normal electrophysiologic studies.[17, 18, 19]

A study by Rivlin et al found that in patients evaluated at 2 weeks and 3 months postoperatively, the efficacy of carpal tunnel release—as measured using the Quick Disabilities of the Arm, Shoulder and Hand questionnaire; symptom severity scale; and functional status scale—did not differ according to preoperative electrodiagnostic grade of CTS.[41]

A study by Rozanski et al indicated that in patients who have undergone isolated carpal tunnel release, the greatest risk factors for symptoms in the ambulatory surgery center or problems within 24 hours after discharge are as follows: male sex, age 45 years or above, and participation of an anesthesiologist in the procedure. However, all such symptoms or problems in the study, which were found in 10% of patients, were minor and transient, according to the investigators. The study involved the records of 400,000 adult patients with CTS, as contained in the National Survey of Ambulatory Surgery database, who underwent isolated carpal tunnel release.[42]

A retrospective study by Pace et al reported that among patients who underwent revision carpal tunnel surgery, self-reported symptom severity and functional scores were the same between patients who underwent repeat decompression alone (17 hands) and those who underwent a combination of decompression and hypothenar fat pad transposition (16 hands).[43]

Consultations

Refer patients with suggested carpal tunnel syndrome to a specialist trained in clinical neurophysiology (usually a neurologist, physiatrist, or physical medicine and rehabilitation specialist) for possible electrophysiologic studies. These test results are important for diagnosis, instigation of appropriate treatment, determination of prognosis, and long-term follow-up.

Other Treatment

Techniques and devices to stretch or manipulate the carpal tunnel have shown some promise but still are not accepted widely.[32]

Guidelines

Guidelines Summary

In February 2016, the American Academy of Orthopaedic Surgeons released an evidence-based clinical practice guideline on the management of CTS. Recommendations based on strong or moderate evidence included the following[40] :

Thenar atrophy is strongly associated with ruling in CTS but is poorly associated with ruling it out

Do not use the Phalen test, Tinel sign, flick sign, or upper limb neurodynamic/nerve tension test (ULNT) criterion A/B as independent physical examination maneuvers to diagnose CTS, because alone, each has a poor or weak association with ruling in or ruling out the condition

Do not use the following as independent history interview topics to diagnose CTS, because alone, each has a poor or weak association with ruling in or ruling out the condition: sex/gender, ethnicity, bilateral symptoms, diabetes mellitus, worsening symptoms at night, duration of symptoms, patient localization of symptoms, hand dominance, symptomatic limb, age, and body mass index

Do not routinely use magnetic resonance imaging (MRI) for the diagnosis of CTS

Diagnostic questionnaires and/or electrodiagnostic studies can be used to aid the diagnosis of CTS

Ketoprofen phonophoresis could provide reduction in pain in comparison with placebo

The surgical release of the transverse carpal ligament should relieve CTS symptoms and improve function

Surgical treatment of CTS should have a greater therapeutic benefit at 6 and 12 months in comparison with splinting, NSAIDs/therapy, and a single steroid injection

There is no benefit to routine postoperative immobilization after carpal tunnel release

There is no benefit to routine inclusion of the following adjunctive techniques: epineurotomy, neurolysis, flexor tenosynovectomy, and lengthening/reconstruction of the flexor retinaculum (transverse carpal ligament)

Buffered lidocaine rather than plain lidocaine should be used for local anesthesia because buffered lidocaine could result in less injection pain

There is no additional benefit to routine supervised therapy over home programs in the immediate postoperative period; no evidence meeting the inclusion criteria was found comparing the potential benefit of exercise versus no exercise after surgery

Medication

Medication Summary

Short (1-2 wk) courses of regular NSAIDs can be of benefit if there is any suggestion of inflammation in the wrist region (eg, flexor tenosynovitis, rheumatoid arthritis). Likewise, if edema is thought to be prominent, then a short course of a mild diuretic may be of benefit.

Nonsteroidal anti-inflammatory drugs

Class Summary

NSAIDs provide pain relief and reduction of inflammation. Reducing inflammation in the structures passing through the carpal tunnel decreases pressure and provides some relief to the compressed nerve.

Naproxen (Aleve, Anaprox, Naprelan, Naprosyn)

Naproxen is used for the relief of mild to moderate pain; it inhibits inflammatory reactions and pain by decreasing the activity of cyclo-oxygenase, which is responsible for prostaglandin synthesis.

Diclofenac (Cambia, Cataflam, Voltaren-XR, Zipsor, Zorvolex)

Diclofenac is one of a series of phenylacetic acids that has demonstrated anti-inflammatory and analgesic properties in pharmacologic studies. It is believed to inhibit the enzyme cyclo-oxygenase, which is essential to the biosynthesis of prostaglandins. Diclofenac can cause hepatotoxicity; hence, liver enzymes should be monitored in the first eight weeks of treatment.

Diclofenac is rapidly absorbed; metabolism occurs in the liver by demethylation, deacetylation, and glucuronide conjugation. The delayed-release, enteric-coated form is diclofenac sodium; the immediate-release form is diclofenac potassium. Diclofenac has relatively low risk for bleeding GI ulcers.

Ibuprofen (Ibuprin, Motrin, Advil, NeoProfen, Caldolor)

Ibuprofen is the drug of choice (DOC) for patients with mild to moderate pain. It inhibits inflammatory reactions and pain by decreasing prostaglandin synthesis. Ibuprofen inhibits cyclo-oxygenase-1 (COX-1) and COX-2 enzymes. This in turn results in decreased formation of prostaglandin precursors.

Indomethacin (Indocin)

Cyclooxygenase-2 inhibitors

Class Summary

Although increased cost can be a negative factor, the incidence of costly and potentially fatal GI bleeds is clearly less with COX-2 inhibitors than with traditional NSAIDs. Ongoing analysis of cost avoidance of GI bleeds will further define the populations that will find COX-2 inhibitors the most beneficial.

Celecoxib (Celebrex)

Inhibits primarily COX-2. Considered an inducible isoenzyme, COX-2 is induced during pain and inflammatory stimuli. Inhibition of COX-1 may contribute to NSAID GI toxicity. At therapeutic concentrations, COX-1 isoenzyme is not inhibited; thus, GI toxicity may be decreased. Seek lowest dose of celecoxib for each patient.

Diuretic agents

Class Summary

Conditions that cause edema may increase pressure in the carpal tunnel. Diuretics may be beneficial in reducing edema.

Hydrochlorothiazide (Microzide)

Inhibits reabsorption of sodium in distal tubules, causing increased excretion of sodium and water, as well as potassium and hydrogen ions.

Follow-up

Further Outpatient Care

See the list below:

Individuals treated conservatively for carpal tunnel syndrome should undergo a follow-up in 4-6 weeks so that the success of treatment interventions can be assessed. Patients who do not achieve the desired results from conservative treatment should be referred for a surgical opinion.

Continued symptoms following carpal tunnel release should prompt referral for repeat electrophysiologic studies.

Deterrence

See the list below:

No conclusive evidence exists of any intervention that can prevent carpal tunnel syndrome.

Complications

See the list below:

Carpal tunnel syndrome may continue to increase median nerve damage, leading to permanent impairment and disability.

Some individuals can develop chronic wrist and hand pain (with or without reflex sympathetic dystrophy).

Prognosis

See the list below:

Carpal tunnel syndrome (CTS) appears to be progressive over time (although with considerable fluctuations from week to week) and can lead to permanent median nerve damage. Whether any conservative management can prevent progression is unclear. Even with surgical release, it appears that the syndrome recurs to some degree in a significant number of cases (possibly in up to one third after 5 years).[18]

Initially, approximately 90% of mild to moderate CTS cases respond to conservative management. Over time, however, a number of patients progress to requiring surgery.

Patients with CTS secondary to underlying pathology (eg, diabetes, wrist fracture) tend to have a less favorable prognosis than do those with no apparent underlying cause.

Patients with normal electrophysiologic studies consistently have much less favorable operative outcomes (and more complications) than do individuals with abnormalities on these tests. Axonal loss on electrophysiologic testing also indicates a less favorable prognosis.

Patient Education

See the list below:

Association versus cause - The association of 2 phenomena does not imply a causal relationship. Using the hands frequently brings on symptoms of carpal tunnel syndrome (CTS), in the same way that exercise brings on angina in patients with coronary artery disease. This association, however, does not necessarily mean that the median nerve damage is caused by use or that it will get worse. (Exercise, in fact, is good for coronary artery disease.)

Avoidance of extremes - If a patient's vocation/avocation involves extreme force/repetition/posture/vibration through the wrist, then it seems prudent to seek ways of avoiding factors that cause or aggravate CTS.

Exercise - BMI and poor fitness levels do appear to be related to the development of CTS.

For patient education resources, see Carpal Tunnel Net, or the Hand, Wrist, Elbow, and Shoulder Center and Arthritis Center, as well as Carpal Tunnel Syndrome.

Contributor Information and Disclosures

Nigel L Ashworth, MBChB, MSc, FRCPC is a member of the following medical societies: Canadian Society of Clinical Neurophysiologists, Australian & New Zealand Association of Neurologists, American Association of Neuromuscular and Electrodiagnostic Medicine, British Medical Association, Canadian Medical Association, Royal College of Physicians and Surgeons of Canada

Milton J Klein, DO, MBA is a member of the following medical societies: American Academy of Disability Evaluating Physicians, American Academy of Medical Acupuncture, American Academy of Osteopathy, American Academy of Physical Medicine and Rehabilitation, American Medical Association, American Osteopathic Association, American Osteopathic College of Physical Medicine and Rehabilitation, American Pain Society, Pennsylvania Medical Society

Benjamin M Sucher, DO, FAOCPMR, FAAPMR is a member of the following medical societies: American Academy of Physical Medicine and Rehabilitation, American Association of Neuromuscular and Electrodiagnostic Medicine, American Osteopathic Association, American Osteopathic College of Physical Medicine and Rehabilitation, Arizona Society of Physical Medicine and Rehabilitation

Ugurlu U, Ozkan M, Ozdogan H. The development of a new orthosis (neuro-orthosis) for patients with carpal tunnel syndrome: its effect on the function and strength of the hand. Prosthet Orthot Int. 2008 Dec. 32(4):403-21. [Medline].